Autoimmune diseases, e.g., multiple sclerosis (MS), insulin-dependent diabetes mellitus (IDDM), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), inflammatory bowel disease (IBD) and psoriasis represent assaults by the body's immune system which may be systemic in nature, or else directed at individual organs in the body. They appear to be diseases in which the immune system makes mistakes and, instead of mediating protective functions, becomes the aggressor (1).
MS is the most common acquired neurologic disease of young adults in Western Europe and North America. It accounts for more disability and financial loss, both in lost income and in medical care, than any other neurologic disease of this age group. There are approximately 250.000 cases of MS in the United States.
Although the cause of MS is unknown, advances in brain imaging, immunology, and molecular biology have increased researchers' understanding of this disease. Several therapies are currently being used to treat MS, but no single treatment has demonstrated dramatic treatment efficacy. Current treatment of MS falls into three categories: treatment of acute exacerbations, modulation of progressive disease, and therapy for specific symptoms. MS affects the central nervous system and involves a demyelination process, i.e. the myelin sheaths are lost whereas the axons are preserved. Myelin provides the isolating material that enables rapid nerve impulse conduction. Evidently, in demyelination, this property is lost. Although the pathogenic mechanisms responsible for MS are not understood, several lines of evidence indicate that demyelination has an immunopathologic basis. The pathologic lesions, the plaques, are characterised by infiltration of immunologically active cells such as macrophages and activated T cells (2).
In U.S. Pat. No. 4,547,511 and U.S. Pat. No. 4,738,971 and in EP 59,698 some derivatives of N-aryl-1,2-dihydro-4-substituted-1-alkyl-2-oxo-quinoline-3-carboxamide are claimed as enhancers of cell-mediated immunity. The compound ##STR2## known as roquinimex (Merck Index 12.sup.th Ed., No. 8418; Linomide.RTM., LS2616, N-methyl-N-phenyl-1,2-dihydro-4hydroxy-1-methyl-2-oxo-quinoline-3-carboxam ide) belongs to this series of compounds. Roquinimex has been reported to have multiple immunomodulatory activities not accompanied with general immunosuppression (3-12).
Furthermore, in U.S. Pat. No. 5,580,882 quinoline-3-carboxamide derivatives are claimed to be useful in the treatment of conditions associated with MS. The particular preferred compound is roquinimex. In U.S. Pat. No. 5,594,005 quinoline-3-carboxamide derivatives are claimed to be useful in the treatment of type I diabetes. The particular preferred compound is roquinimex. In WO 95/24195 quinoline-3-carboxamide derivatives are claimed to be useful in the treatment of IBD. Particularly preferred compounds are roquinimex or a salt thereof. In WO95/24196 quinoline-3-carboxamide derivatives are claimed to be useful in the treatment of psoriasis. Particularly preferred compounds are roquinimex or a salt thereof.
In clinical trials comparing roquinimex to placebo, roquinimex was reported to hold promise in the treatment of conditions associated with MS (13, 14). There are, however, some serious drawbacks connected to roquinimex. For example, it has been found to be teratogenic in the rat, and to induce dose-limiting side effects in man, e.g., a flu-like syndrome, which prevents from using the full clinical potential of the compound.
Further, in WO 92/18483 quinoline derivatives substituted in the 6-position with a R.sub.A S (O).sub.n -group (R.sub.A =lower alkyl or aryl; n=0-2) are claimed, which possess an immunomodulating, anti-inflammatory and anti-cancer effect.
The substitution, i.e., type and pattern, of the above, specifically mentioned, compounds places them outside the scope of the present invention.